1. Field of the Invention
This invention pertains to sheet material handling and fabricating components. The sheet material is of the self-shape-sustaining type, such as plastic, wood or metal.
2. Description of the Prior Art
In many industries, particularly the aerospace industry, there is a need for the mechanized production of a relatively few irregularly shaped sheet material parts. For example, only 2 or 300 such parts may be needed in a year. Presently, these parts are made by first cutting a templet and then, either by hand or with limited machinery, cutting the shape of the templet in the sheet material. After the part is cut, a considerable amount of manual deburring of the cut edge is required, with still more surface finishing following. The cost of such individual parts is quite high and since a particular industry may need as many as 2 or 3 thousand different shaped parts manufactured in this way, the ultimate cost is considerable.
There is, therefore, a need in the sheet material handling and fabricating industry for an apparatus or method to mechanize the production of a large variety of relatively few parts of sheet material. While the numerically controlled punch press is a useful tool for satisfactorily fabricating holes or the like internally in the part, it is not satisfactory for cutting the peripheral shape of such irregularly shaped parts, and thus cannot fully satisfy the need for full mechanization.
One difficulty in cutting a peripheral shape in moving sheet material is that of supporting the sheet in close proximity to the cutting element without increasing the friction between the sheet and the support. Additionally, it is desirable when cutting with a band saw blade, for example, to reduce vibration caused by the blade engagement with the sheet.